(1) Field of the Invention
The present invention relates to susceptors for supporting and heating semiconductor wafers, liquid panels, silicon single crystal wafers for solar cells, etc.
(2) Related Art Statement
As the susceptors for supporting and heating the semiconductor elements, the liquid panels, the silicon single crystal wafers or the like, it is proposed that a heat-generating element is buried in a susceptor, and an electrode cable etc. are housed in slender supporting rod or rods, a supporting tube or a protective tube.
It has been increasingly demanded that the diameter of the wafers to produce the semiconductor wafers is increased or the size of the liquid panels is made lager. For this purpose, it has been demanded to make the size of the susceptors lager. Thus, it has been demanded to make the diameter of the planar heat-conductive layers of the susceptors not less than 300 mm. However, as the diameter of the heat-conductive layer increases, it becomes very difficult to keep the temperature of the heating surface of the planar heat-conductive layer uniform, which poses a problem difficult to be solved. For, if the temperature distribution of the heating surface of the planar heat-conductive layer becomes non-uniform, the susceptor will be unacceptable. Particularly if a plurality of, for example three, supporting rods or protective tubes are attached to the planar heat-conductive layer to realize a large-size susceptor, the temperature of the heating surface becomes particularly more non-uniform.